Muhammad A. Sadiq^1,2,*, Nadeem Abbas³, Haitham M. S. Bahaidarah⁴, Mohammad Amjad⁵

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.2, pp. 471-486, 2023, DOI:10.32604/fdmp.2022.021133

Abstract We present the results of an investigation into the behavior of the unsteady flow of a Casson Micropolar nanofluid over a shrinking/stretching curved surface, together with a heat transfer analysis of the same problem. The body force acting perpendicular to the surface wall is in charge of regulating the fluid flow rate. Curvilinear coordinates are used to account for the considered curved geometry and a set of balance equations for mass, momentum, energy and concentration is obtained accordingly. These are turned into ordinary differential equations using a similarity transformation. We show that these equations have dual solutions for a number… More >

Andrianantenaina Marcelin Hajamalala^1,*, Ratovonarivo Noarijaona¹, Zeghmati Belkacem²

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.6, pp. 1737-1748, 2022, DOI:10.32604/fdmp.2022.022047

Abstract This work deals with the modeling of the unsteady Newtonian fluid flow associated with an open cylindrical reservoir. This reservoir presents a hole on the right bottom wall. Fluid volume variation, heat and mass transfers are neglected. The unsteady governing equations are based on the conservation of mass and momentum. A finite volume technique is used to solve the non-dimensional equations and related boundary conditions. The algebraic system of equations resulting from the discretization process are solved by means of the THOMAS algorithm. For pressure-velocity coupling, the SIMPLE algorithm (Semi Implicit Method for Pressure Linked Equations) is used. Results for… More >

Ting Zhang¹, Denghao Wu^1,2,*, Shijun Qiu², Peijian Zhou¹, Yun Ren³, Jiegang Mou¹

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.5, pp. 1349-1361, 2022, DOI:10.32604/fdmp.2022.019617

Abstract Stall phenomena increase the complexity of the internal flow in centrifugal pump impellers. In order to tackle this problem, in the present work, a large eddy simulation (LES) approach is applied to determine the characteristics of these unstable flows. Moreover, a vorticity identification method is used to characterize quantitatively the vortex position inside the impeller and its influencing area. By comparing the outcomes of the numerical simulations and experimental results provided by a Particle Image Velocimetry (PIV) technique, it is shown that an apparent “alternating stall” phenomenon exists inside the impeller when relatively small flow rate conditions are considered. The… More >

Senchun Miao^1,2,*, Hongbiao Zhang¹, Wanglong Tian¹, Yinqiang Li²

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1021-1036, 2021, DOI:10.32604/fdmp.2021.016925

Abstract To study the unsteady flow and related energy conversion process in the volute of a pump-as-turbine (PAT) device, six different working conditions have been considered. Through numerical calculation, the spatio-temporal variation of static pressure, dynamic pressure, total pressure and turbulent energy dissipation have been determined in each section of the volute. It is concluded that the reduction of the total power of two adjacent sections of the PAT volute is equal to the sum of the power lost by the fluid while moving from one section to the other and the power output from the two adjacent sections. For a… More >

Jilin Zhang^1,4,5, Xuechao Liu^1,5, Jian Wan^2,1,5, Yongjian Ren^1,5, Binglin Xu^1,5, Jianfan He^1,5, Yuchen Fan^1,5, Li Zhou^1,5, Zhenguo Wei⁶, Juncong Zhang⁶, Jue Wang³

Intelligent Automation & Soft Computing, Vol.25, No.3, pp. 527-546, 2019, DOI:10.31209/2019.100000109

Abstract A numerical optimization algorithm for unsteady flows of rotor based on web service is proposed. Space discretization uses the finite volume method, time discretization uses the implicit dual-time steps method, and turbulence model uses the Spalart–Allmaras (S–A) model. In order to efficiently use the computing resources of the cluster, a service-oriented service computing architecture is used in a parallel computing service program. In order to realize the load balance of hybrid grid partition, the grid is partitioned by Metis Library. Meanwhile, data communication based on Message Passing Interface (MPI) technology guarantees the consistency of convergence between parallel algorithm and serial… More >

Jiacheng Dai¹, Jiegang Mou^{1, *}, Tao Liu¹

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.2, pp. 161-179, 2020, DOI:10.32604/fdmp.2020.06613

Abstract The automobile engine pump is an important part of the automobile cooling system, and has a direct influence on the engine performance. Based on the SST k-ω turbulence model, unsteady numerical simulation for an automobile engine pump with different tip clearances was carried out by Fluent. To study the flow field characteristics and pressure fluctuation, the characteristics of secondary flow distribution in volute are also analyzed. The result shows that the pressure fluctuation characteristics of the flow field show obvious periodic variation at different levels of tip clearances. The peak value of pressure fluctuation at each monitoring point is dependent… More >

Alvaro Valencia¹

Molecular & Cellular Biomechanics, Vol.1, No.3, pp. 221-232, 2004, DOI:10.3970/mcb.2004.001.221

Abstract Flow dynamics play an important role in the pathogenesis and treatment of intracranial aneurysms. The evaluation of the velocity field in the aneurysm dome and neck is important for the correct placement of endovascular coils, and the temporal and spatial variations of wall shear stress in the aneurysm are correlated with its growth and rupture. This numerical investigation describes the hemodynamic in two models of terminal aneurysm of the basilar artery. Aneurysm models with a aspect ratio of 1.0 and 1.67 were studied. Each model was subject to physiological representative waveform of inflow for a mean Reynolds number of 560.… More >

Wei Huang^∗,†, Qinlian Zhou^†,‡, Jian Gao^‡, R. T. Yen^‡,§,¶

Molecular & Cellular Biomechanics, Vol.8, No.2, pp. 105-122, 2011, DOI:10.3970/mcb.2011.008.105

Abstract A continuum model was introduced to analyze the pressure-flow relationship for steady flow in human pulmonary circulation. The continuum approach was based on the principles of continuum mechanics in conjunction with detailed measurement of vascular geometry, vascular elasticity and blood rheology. The pulmonary arteries and veins were considered as elastic tubes and the "fifth-power law" was used to describe the pressure-flow relationship. For pulmonary capillaries, the "sheet-flow" theory was employed and the pressure-flow relationship was represented by the "fourth-power law". In this paper, the pressure-flow relationship for the whole pulmonary circulation and the longitudinal pressure distribution along the streamlines were… More >

Tong-qing Guo, Zhi-liang Lu¹

CMC-Computers, Materials & Continua, Vol.2, No.2, pp. 105-112, 2005, DOI:10.3970/cmc.2005.002.105

Abstract In this paper, a rapid deforming technique is developed to generate dynamic, three-dimensional, multi-block, mesh. The second-order Runge-Kutta time-marching method is used to solve the structural equations of motion. A dual-time method and finite volume discretization are applied for the unsteady Euler/Navier-Stokes equations to calculate the aerodynamic forces, in which the physical time step is synchronous with the structural equations of motion. The Spalart-Allmaras turbulence model is adopted for a turbulent flow. Due to mass dissimilarity, exiting in flutter calculations for a compressible flow, methods of variable mass and variable stiffness are developed to calculate the dynamic pressure of flutter… More >

Anant Diwakar¹, D. N.Srinath¹, Sanjay Mittal¹

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.1, pp. 61-90, 2010, DOI:10.3970/cmes.2010.069.061

Abstract Aerodynamic shape optimization of airfoils is carried out for two values of Reynolds numbers: 10³ and 10⁴, for an angle of attack of 5^o. The objective functions used are (a) maximization of lift (b) minimization of drag and (c) minimization of drag to lift ratio. The surface of the airfoil is parametrized by a 4^th order non-uniform rational B-Spline (NURBS) curve with 61 control points. Unlike the efforts in the past, the relatively large number of control points used in this study offer a rich design shape with the possibility of local bumps and valleys on the airfoil surface. The… More >